Introduction

Coverages - as per OGC, ISO, and INSPIRE standardization - constitute a unifying paradigm for digital representations of space/time varying phenomena, concretely: spatio-temporal regular and irregular grids, point clouds, and general meshes. In particular, multi-dimensional datacubesfall under this category, such as 1-D sensor time series, 2-D satellite imagery, 3-D x/y/t image time series and x/y/z geoscientific models, 4-D x/y/z/t climate and ocean data sets, and more.

This data model is accompanied by a modular service model, the Web Coverage Service (WCS) suite of standards. Functionality of this Web API ranges from flexible datacube access and subsetting up to complex geo datacube analytics with the Web Coverage Processing Service(WCPS) datacube language.

While still fomat-independent, this conceptual overage model is conformance testable down to pixel level and harmonized with GML, SWE, and other OGC standards, thereby concretizing the abstract and therefore not interoperable ISO 19123 model.

About

This site is part of the Open Geospatial Consortium (OGC) and maintained by its Coverages Domain Working Group (Coverages.DWG) which uses this site for providing information about standardization of coverages.The OGC Coverages.DWG is a community oriented working group established for facilitating exchange on the OGC coverage data and service standards. The Coverages.DWG does not directly revise OGC standards, but rather enables collaboration and communication between groups with spatio-temporal modeling interests. See also the Temporal.DWGwhich specifically addresses temporal data aspects.

This Twiki as well as the corresponding email list provide information about the standards, including tutorials and the authoritative specification sources. Further, it constitutes a public forum for communication. Anyone can edit this wiki, but, of course, responsibly. Instructions can be found on the TWiki Text Formatting Rulespage.

Several publications explain and exemplify use of WCS, as well as the technological advances made with WCS 2. Whenever writing scientific articles about coverages and WCS, do the editors a favour and cite their scientific work, following good practice - much appreciated!

News

September 2017: At the Southampton TC meeting the Coverages.DWG has moved to approve establishing a Datacube Domain Working Group; close collaboration between the Coverages.DWG and the forthcoming Datacube.DWG is planned as the OGC datacube standard is the Coverage Implementation Schema.

April 2017: CIS 1.1 is adopted by OGC as an Interface Standard. This opens the way for introducing CIS 1.1 to ISO to become the next version of ISO 19123-2.

November 2015: Following successful presentation in the OAB, the new OGC Coverage Implementation Schema (CIS) 1.1 is now being rolled out for public comments.

October 2012: GeoTIFF and JPEG2000 format encodings for coverage have been released by the WCS.SWG, recommending them for public Request for Comment (RFC).

August 2012: By vote of OGC, the WCS GET-KVP corrigendum version 1.0.1 has been accepted. It provides a slight modification necessary for the format encoding flexibility introduced with GMLCOV 1.0.1 and WCS 2.0.1.

August 2012: The Range Subsetting Extension has been released by the WCS.SWG, recommending it for public Request for Comment (RFC).

August 2012: the OGC Coordinate Reference System (CRS) Name Type Specification (NTS) [OGC 11-135] has been released by the WCS.SWG, recommending it for public Request for Comment (RFC) as a Best Practice Paper (available on this page); this document establishes a uniform naming system for CRS identifiers, allowing general multi-dimensional CRSs.

July 2012: Corrigenda have been published for WCS Core and GML Application Schema - Coverages (GMLCOV).

May 2012:rasdaman is the first WCS implementation to pass the WCS Core test suite and, therefore, becomes candidate reference implementation.

December 2011:a proposal for OGC Name Type Specification for Coordinate Reference Systems (CRSs) has been presented, together with an open-source registry implementation. During the next weeks this resolver will be set up as a prototype service by OGC.

The CRS Name Type Specificationis adopted by OGC, and the corresponding CRS resolver is running at OGC -- from now on, spatial, temporal, and "abstract" coordinate axes can be treated alike, and can be mixed freely (such as temporal WGS84, or CRSs for x/t and y/z slices as produced by a WCS)

Conformance Testing

WCS: conformance tests are established and available for WCS Core; GET KVP; XML/POST; SOAP; Range Subsetting; Scaling; Interpolation; Processing; still in the pipeline is CRS.

Note that the list above is not authoritative (the page maintainers do not regularly check the links) and does not constitute any endorsement nor a statement of OGC nor anybody else about conformance. Information is provided as is, without any warranty.

WCS History

WCS 2.0 has several significant advantages over previous versions: it relies on the GML coverage model, leading to increased interoperability as well as harmonization across OGC standards; among the main features are:

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